1. Field of the Invention
The invention relates generally to devices for adjusting clearance between surfaces of a relatively mounted component part holder and its support structure, and more particularly for adjustment of axial clearance (end-play) between the rotor and the stator support structure in an electric motor.
2. Description of the Prior Art
In the typical prior art, in particular as it relates to small electric motors, an armature has an axial shaft supported by bearings mounted in a stator housing structure. Manufacturing tolerance problems encountered in large scale production of such items precludes consistent rotor end-play from sample to sample. Accordingly, some device or structure is required to permit adjustment of end-play as a step in the manufacture of such electric motors.
One prior art device is described in German Pat. No. 15 38 921. In that conventional device the rotationally mounted component part, i.e. the cylinder and surface of a squirrel-cage rotor, is provided with a hollow (indented) space. While adjusting the distance, a self-curing plastic compound is inserted into this hollow space, in which a spacer is pressed more or less deep, and is fixed there in position after the curing of the compound.
Any prior art process relying on insertion of a self-curing material initially in liquid or semi-liquid form presents disadvantages. One of these disadvantages resides in the fact that a self-curing plastic compound, such as a casting resin, owing to its sticky consistency, presents handling difficulties in quantity production of the components. It unavoidably soils the work as well as the work environment and can only be well handled in fully automatic production involving high investment in tooling and machinery. Another disadvantage resides in that the compound itself requires a curing time, so that components on which the adjustment has been carried out cannot be put into operation immediately after the adjustment for the purpose of carrying out intermediate checks or for further processing purposes.